The invention relates to a central locking drive for the actuation of various locking functions of a door lock, especially in motor vehicles"" with two drive members, which are each displaceable between an inoperative position and an activated position.
In addition to the known locking functions of central locking and central unlocking, the other function mostly demanded of present-day central locking systems is that of central security, in which unlocking of the external door handle and/or opening of the door by operating the internal door handle is prevented. This is required for anti-theft protection, since a vehicle door in this position cannot be readily opened even after smashing in a vehicle window. In order to be able to actuate this third locking function, it must be possible for the central locking drive to run into a third position, which can be achieved, for example, by means of an additional second drive member, such as a motor or a lifting magnet, or by purposely assuming an intermediate position of the first drive member with the aid of a switch or potentiometer, for example, the two limit stops of the drive member and the intermediate position defined by the switch or the potentiometer defining the three operating positions in the case of an intermediate position.
Yet a further locking function, that is child safety, is necessary on the rear doors of a motor vehicle. This is basically intended to prevent opening of the door by means of the internal door handle, but in the central locking position to permit unlocking of the external door handle by operating the internal door handle, since otherwise with central locking and child safety activated the central security function would virtually be engaged.
The additional function has hitherto generally been achieved by mechanical intervention in the lock with the door open, whereas an additional drive member is required for integration into the central locking drive. Consequently either three drive members at correspondingly high cost or a solution with two drive members and an electrical switch for detecting an intermediate position are required in order to achieve all the above-mentioned locking functions electrical switches however, being just as highly expensive in terms of circuitry as the detection of intermediate positions by means of potentiometers and having a certain susceptibility to malfunction.
The object of the present invention is to create a central locking drive that relies on just two drive members and permits actuation of at least the desired locking functions central locking, central unlocking central security and child safety simply by displacement of the drive members between their limit positions.
According to the invention the object is achieved by a central locking drive of the type initially described, in which an operating element is provided which is moveable between a neutral position, which it assumes when the two drive members assume their inoperative position, and at least one operating position, the attainment of a particular operating position of the operating element being dependent upon the order in which the two drive members are activated.
In the solution according to the invention the additional locking function is defined by the order in which the two drive members are actuated, there being no need to arrest these in intermediate positions. In terms of control technology the encountering of limit stops is very simple, the differing sequence for the actuation of the two drive members also being very easily accomplished in terms of control technology. The elimination of a third drive member or an additional electrical switch provides for savings in the overall space required and in the weight of the central locking drive, savings also being achieved through being able to dispense with the corresponding electrical wiring.
Provision is preferably made so that a first drive member, in its activated position, deadlocks or interrupts the connection between an internal door handle and the door lock, and the second drive member, in its activated position, deadlocks or interrupts the connection between an external door handle and the door lock. An interruption or deadlocking of the connections by the drive members in their inoperative position is also feasible depending on the definition. The connection between the door handles and the door lock may be of mechanical or electrical design.
In a further preferred embodiment of the invention it is proposed that the operating element be moveable by operation of the first drive member and subsequently moving the second drive member into a first operating position, in which it is possible to unlock the external door handle by operating the internal door handle.
In a central locking drive of this type the aforementioned locking functions are configured so that the central unlocking function is engaged when the drive members are in the inoperative position, the child safety function with external door handle unlocked is engaged when the first drive member is activated and the second drive member is in the inoperative position, the central locking function with the facility for opening the door from inside is engaged when the second drive member is activated and the first drive member is in the inoperative position, the child safety and central locking function with the facility for unlocking the external door handle by operating the internal door handle is engaged when the first drive member is activated first and the second drive member is activated subsequently, and the central security function is engaged when the second drive member is activated first and the first drive member is activated subsequently.
It is also feasible that in one operating position the operating lever might interrupt or deadlock a facility for unlocking the external door handle by means of the internal door handle. Such a design is conceivable in combination with a facility, purposely established by the operating element in its first operating position, for unlocking the external door handle by means of the internal door handle or even in the case of a central locking drive, in which such a facility exists whenever the operating element is not in a certain operating position.
Interacting cam elements are preferably provided on the operating element and on each of the drive members respectively, which on activation of the first drive member cause the operating element to be shifted into a first intermediate position and on subsequent activation of the second drive member cause the operating element to be shifted further into the first operating position, and on initial activation of the second drive member cause the operating element to be shifted into a second intermediate position and on subsequent activation of the first drive member cause it to be shifted into a limit position or second operating position other than the first operating position.
Such a solution for operation of the first operating element by the drive members in which the cam elements provided on the operating element have, for example, lifting flanks inclined in relation to the direction of movement of the cam elements on the drive members permits simple mechanical driving of the operating element into the required operating position by engaging the limit positions of the drive members.
The operating element is preferably returned towards its neutral position by means of a return spring. Alternatively a mechanical drive into the neutral position by returning the drive members to their inoperative position is also feasible, for example.
The central locking drive according to the invention may in principle rely on widely differing types of drive members such as motors or electromagnets for example. Thus the drive members in a preferred embodiment of the invention have electric drive motors which are each traversable between two stops which represent the inoperative position or the activated position of the respective drive member. Electric drive motors are of very compact construction, have only a relatively low power input and are very quiet in operation, it being possible to detect the stop positions for switching off the drive motor by detecting the power input. The drive motors preferably drive spindles which engage with adjusting nuts on which the cam elements are arranged. In order to guide the operating lever accurately between its various positions it may be pivotally mounted, although a linear guide, for example, is also conceivable.